如何让组合框的列表更宽广？ [英] How can I make combobox's list wider?

问题描述

import javax.swing.*;

public class test
{   
    public static void main(String[] args) throws Exception
    {
        JFrame frame = new JFrame("Test");
        frame.setDefaultCloseOperation(WindowConstants.EXIT_ON_CLOSE);
        frame.setSize(120,80);      
        JComboBox cb = new JComboBox();
        cb.addItem("A very long combo-box item that doesn't fit no. 1");
        cb.addItem("A very long combo-box item that doesn't fit no. 2");
        frame.add(cb);
        frame.validate();
        frame.setVisible(true);
    }
}

如何让组合框项目出现在所有文本都可见的方式？

现在我有这样的东西：



我不想在折叠时更改组合框的大小。

我只想增加展开部分的宽度。

How can I make combo-box items to appear in the way that all their text is visible?
Now I have something like this:

I don't want to change size of combo-box while collapsed.
I just want to increase width of the expanded part.

推荐答案

我认为此可能会有所帮助。

I think this may help.

来自链接的代码

public class WiderDropDownCombo extends JComboBox {

    private String type;
    private boolean layingOut = false;
    private int widestLengh = 0;
    private boolean wide = false;

    public WiderDropDownCombo(Object[] objs) {
        super(objs);
    }

    public boolean isWide() {
        return wide;
    }

    // Setting the JComboBox wide
    public void setWide(boolean wide) {
        this.wide = wide;
        widestLengh = getWidestItemWidth();

    }

    public Dimension getSize() {
        Dimension dim = super.getSize();
        if (!layingOut && isWide())
            dim.width = Math.max(widestLengh, dim.width);
        return dim;
    }

    public int getWidestItemWidth() {

        int numOfItems = this.getItemCount();
        Font font = this.getFont();
        FontMetrics metrics = this.getFontMetrics(font);
        int widest = 0;
        for (int i = 0; i < numOfItems; i++) {
            Object item = this.getItemAt(i);
            int lineWidth = metrics.stringWidth(item.toString());
            widest = Math.max(widest, lineWidth);
        }

        return widest + 5;
    }

    public void doLayout() {
        try {
            layingOut = true;
            super.doLayout();
        } finally {
            layingOut = false;
        }
    }

    public String getType() {
        return type;
    }

    public void setType(String t) {
        type = t;
    }

    public static void main(String[] args) {
        String title = "Combo Test";
        JFrame frame = new JFrame(title);

        String[] items = {
                "I need lot of width to be visible , oh am I visible now",
                "I need lot of width to be visible , oh am I visible now" };
        WiderDropDownCombo simpleCombo = new WiderDropDownCombo(items);
        simpleCombo.setPreferredSize(new Dimension(180, 20));
        simpleCombo.setWide(true);
        JLabel label = new JLabel("Wider Drop Down Demo");

        frame.getContentPane().add(simpleCombo, BorderLayout.NORTH);
        frame.getContentPane().add(label, BorderLayout.SOUTH);
        int width = 200;
        int height = 150;
        frame.setSize(width, height);
        frame.setVisible(true);

    }
}

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